Real Madrid could be set to make a sensational £30m bid to Chelsea for their long-serving goalkeeper Petr Cech, as they look set to offload their unsettled star Iker Casillas this January, CaughtOffside understands.

The Spanish shot-stopper has long been unhappy at the club after being dropped by previous manager Jose Mourinho earlier this year, and with new boss Carlo Ancelotti continuing to favour Diego Lopez as a starter in goal.

However, Ancelotti remains unconvinced that Lopez is the long-term solution between the sticks for Los Blancos, and wants a world class player brought in when Casillas is eventually moved on.

With the likes of Arsenal and Manchester City interested in securing the services of Casillas, the 32-year-old could be set for an exit in the middle of the season, as he will no doubt be keen to be playing regular first-team football ahead of next summer’s World Cup, where he will be hoping to captain holders Spain in Brazil.

Valued by his club at around £20m, Casillas’ sale should bring in sufficient funds for Real to launch a big-money bid for Cech, though the Blues will be desperate to hold on to their long-time number one.

Mourinho, now in charge of Chelsea after leaving Real Madrid, will possibly be keen to hold off negotiations until the summer, when the London club will welcome back promising youngster Thibaut Courtois from his time out on loan with Atletico Madrid.

Although it has been widely expected that Courtois would make way at the end of this season on a permanent deal, it could be that Mourinho is ready to make the Belgian his new number one if a good enough offer comes in for Cech. Juventus’ Gianluigi Buffon is currently the most expensive goalkeeper in the history of the game after joining the Turin club for £32m in 2011, and it could be that the Blues shot-stopper will end up surpassing that record.

Cech has been at Stamford Bridge since 2004, and has helped the team to one of the most successful periods of their entire history, but with Courtois looking likely to develop into one of the best goalkeepers in the world, Mourinho may feel it is time to make him his long-term starter in goal, with Cech now 31 and approaching the twilight of his career.

Courtois, 21, has been linked with big clubs such as Barcelona, who are also facing something of a goalkeeping crisis, and it is understood that the Chelsea manager is not keen to let such a bright prospect leave to another big club.

Real boss Ancelotti worked with Cech during his time as manager of Chelsea, and has also been linked with another raid on his old club recently, with Brazilian midfielder Ramires emerging as one of his several targets for January.

The Spanish giants are keen to strengthen their squad after falling behind to rivals Barcelona and Atletico in this season’s La Liga title race.